I SUPPOSE it was being on holiday in Britain that did it, but it struck me last week what a pessimistic lot the nation’s weather forecasters seem to be.

Not a single day was forecast to be reliably dry and yet, in the event, only two days turned out to be wet – and on one of those the light drizzle hardly made it worth putting on a coat.

The best day, when rain was not forecast until the late afternoon (and then didn’t show up) was predicted to consist mostly of “sunny intervals” which, as the sun did disappear for a few brief periods, was I suppose technically, correct. The weather would, however, have been more accurately described as “cloudy intervals”, but when did you ever hear that in a forecast?

The predictions were equally pessimistic the previous week. There was, perhaps, greater justification on this occasion as I happened to be in Wales rather than East Anglia, but three consecutive days forecast to be mainly wet produced no more than five minutes’ light rain in mid morning, followed lengthy periods of sunshine later on.

When showery rain is expected, it is of course impossible to predict exactly where and when it will fall, but do the forecasters have to err so far on the side of caution? While a pleasant surprise is better than an unpleasant one, a dire weather forecast for what turns out to be, essentially, a fine day must be a source of enormous frustration for those running tourism-related businesses.

True, a forecast for rain which keeps people away from the beach will produce some winners as well as losers but, with such a forecast likely to keep day visitors at home, the result must still be a substantial net loss.

If forecasters feel obliged to indicate rain when there is the slightest chance of a shower, could they not at least accompany it with an assessment of the percentage risk?

While a 10% chance of a light shower in any particular location is one which many holidaymakers or event planners might well feel inclined to ignore, a 40% risk is likely to result in a different judgement.

At present, however, most forecasts fail to make any clear distinction between the two, to the potential loss of the tourism industry.

It is true that a forecast involving a 50% chance of rain might be viewed as something of a cop out, meaning in effect: “It might rain or it might not, and either way don’t blame us”, but for the most part an assessment of the percentage risk would be helpful.

And such an approach would still protect the reputation of forecasters. After all, if you get wet when the forecast was for only a 10% chance of rain, you will have no way of knowing whether you have just been unlucky or whether it has been chucking it down everywhere.